Does your garage door open but not close? My garage door will start to close move a few inches and reverse back up. The garage door can be very sensitive sometimes. In San Diego we have the beautiful sun out all the time. Believe it or not the sun can stop your garage door from closing. The garage door opener sensors are what stop the garage door from closing. The garage door opener sensors are located on both sides of the garage door near the floor. Usually 4″ to 6″ up. Most garage door sensors have a LED light to indicate the alignment. The lights are different colors. This is so you can tell the deference between the Receiver and the Transmitting sensors. The Transmitting sensor LED as long as it is wired correctly will stay constant lit. The receiver sensors LED will not be illuminated when the transmitting sensor is not aligned and facing each other. To correct this issue.